Journal of Student Research 2015

140 Journal Student Research decreases and only plants which are able to obtain nutrients in other ways will thrive (Mitsch & Gosselink, 2007). In conjunction with our hypotheses regarding P and chlorophyll a, we hypothesized that pH and plant species richness will have a negative relationship; less acidic (higher pH) environ ments will be dominated by competitive plant species due to increased nutri ent levels, thereby reducing wetland species richness. Microtopographic features, such as small pools, logs, or hummocks, affect plant microhabitats (climate, sunlight, moisture availability, and organic matter) within wetlands and, in turn, influence species persistence. Studies on restored wetlands suggest that those with more microtopograph ic variation had higher species richness (Tweedy et al., 2001). Variation in microtopography leads to more niches being available for plant species and a wider variety of microenvironmental conditions. Plant diversity in created wetlands was positively related to tortuosity (amount of bend or twist) and elevation difference, both measures of microtopography (Moser, Ahn, & Noe, 2007). These studies support the hypothesis that microtopography (created by hummocks, logs, and stumps) will increase species richness in ephemeral ponds. Water depth and hydroperiod (the duration of water in the wetland) also affect species richness. Shallower wetlands tend to have more species than deep wetlands (Cherry & Gough, 2006), perhaps due to more microtopo graphic variation. In addition, only specialized aquatic plant species can tolerate deep water environments (Mitsch & Gosselink, 2007). We hypothe sized that wetland water depth would have a negative effect on plant species richness. Although substantial work has been done on plant species rich ness-environment relationships in wetlands, little has been done in ephemeral ponds. We were particularly interested in the effects of environmental factors on plant species richness and whether EPs or PWs have higher species rich ness. Because little is known about EP plant communities, a multiple scale, multiple factor study was needed. Our study had multiple objectives. We aimed to determine 1) which type of wetland had higher species richness, permanent or ephemeral, 2) the important environmental predictors of plant species richness within EPs and PWs, and 3) the effects of microtopography on species richness at multiple scales. Methods Study Site This study was conducted in 57 wetlands (39 EPs and 18 PWs) in the 1,856 ha Chippewa Moraine State Recreation Area of Chippewa County,